The present invention relates generally to the field of information security, and more particularly to access control.
There are a variety of processes of distinguishing computer input from human input, a subset of these processes are challenge-response tests. An example of a challenge-response test is a “completely automated public Turing test to tell computers and humans apart,” or CAPTCHA. One use for these challenge-response tests is as feedback-based entrance systems to ensure against the systematic entrance of an automated application to a location, for example, as gatekeepers for email accounts, blog or forum posts, and sensitive websites. Because of the pervasive implementation of these processes, methods and formats have been expanded: from text-based to picture- and video-based; to help digitize books; to show advertisements; and to perform surveys.